[180.06] Determining the Types and Redshifts of Supernova Spectra

We present an algorithm used by members of the ESSENCE Team
to identify the types of supernova spectra and determine
their redshift. This algorithm, based on the correlation
techniques of Tonry and Davis (1979), is implemented in the
SuperNova IDentification code (SNID; Blondin et al., in
prep). We show that this code can enable one to determine
whether a noisy spectrum is more likely to be that of a Type
Ia supernova (SN Ia), as opposed to other types (e.g., SN
Ib/c). Furthermore, by comparing the correlation redshifts
obtained using SNID with those determined from narrow
emission/absorption lines in the supernova host galaxy, we
show that accurate redshifts (with a typical error \sigmaz
= 0.01) can be determined for SN Ia when a spectrum of the
host galaxy is unavailable.

This work is partially supported by grant AST-0443378 from
the US National Science Foundation.